IntroductionWater-hardening tool steels are also known as group W steels. This group consists of three types, namely, W1, W2, and W3. The main alloying element found in group W steels is carbon. To increase the wear resistance and hardenability of the W steels, a small amount of chromium can be added. By adding vanadium, the grain size is maintained, which enhances the toughness of the steels. The group W steels have low resistance to softening at high temperatures and are inexpensive.

The W1 steel is one of the most commonly available water hardening tool steel grades and can be easily hardened by heating and quenching in water. However, this alloy does undergo some amount of distortion during quenching. The following datasheet will provide details of W1 water-hardening tool steels.

Other DesignationsOther designations that are equivalent to AISI W1 tool steels include:

ASTM A686

SAE J437 (W108), (W109), (WhO), (W112)

SAE J438 (W108), (W109), (W110), (W112)

UNS T72301

Fabrication and Heat TreatmentMachinabilityThe machinability of W1 steels is very good as they are plain carbon steels with 100% rating based on which other tool steels are compared.FormingW1 steels can be easily formed using conventional methods.WeldingW1 steels are weldable using all the standard methods.Heat TreatmentThe treatment depends upon the intricacy of the part or section size. W1 steels with large sections or intricate shapes have to be slowly preheated to 593°C (1100°F) and then the temperature should be slowly increased to 816°C (1500°F). The steels should be maintained at the same temperature for 10 to 30 minutes and finally water or brine quenched.ForgingForging of the W1 steels can be performed at 1038°C (1900°F) down to 816°C (1550°F) but not below 843°C (1500°F).Hot WorkingW1 steels can be hot-worked.Cold WorkingW1 steels in the annealed condition have very good ductility and can be easily cold worked using conventional methods.AnnealingAnnealing has to be performed at 760°C (1400°F) followed by slow furnace cooling at 4°C (40°F) per hour or less.TemperingTempering of the W1 steels is performed at 177-343°C (350-650°F) to realize Rockwell C hardness of 64 to 50.ApplicationsThe W1 steels are mainly used for cold heading, hand-operated metal cutting tools, reamers and embossing taps. It is also used for cutlery.